Adjustable tripod assembly

ABSTRACT

A support apparatus of adjustable height having at least one leg assembly with a first leg unit, a second leg unit and a third leg unit. The first and second leg units are slidably movable relative to each other, and the second and third leg units are slidably movable relative to each other. A first fixing clamp selectively locks and unlocks the first leg unit relative to the second leg unit, and a second fixing clamp selectively locks and unlocks the first leg unit relative to the second leg unit. First and second actuating levers are independently actuatable to selectively lock and unlock the first and second fixing levers. The first and second actuating clamps can be operated simultaneously to simultaneously lock or unlock both of the first and second fixing clamps, irrespective of the positions of the first, second and third leg units relative to each other.

FIELD OF THE INVENTION

The present invention relates to a support means of adjustable height.The present invention is particularly suitable for use as a tripod, suchas a tripod used in still photography or moving picture recording ortransmitting. The present invention also relates to a leg assembly foruse in support means.

BACKGROUND OF THE INVENTION

Support means of adjustable height, such as tripods, are known in thepresent art. One such support means is known as a two stage tripod. Suchtripods have three leg assemblies, with each leg assembly comprising afirst leg unit, a second leg unit and a third leg unit. In order toenable the height of the tripod to be adjusted, the first and second legunits are slidably movable relative to each other and the second andthird leg units are also slidably movable relative to each other. Eachleg assembly also includes a first fixing means for selectively lockingand unlocking the first leg unit relative to the second leg unit and asecond fixing means for selectively locking and unlocking the second legunit relative to the third leg unit. When the first fixing means is inthe unlocked position, the first and second leg units are movable withrespect to each other, whilst in the locked position the first andsecond leg units are held in fixed (or locked) in relation to eachother. The second fixing means operates in a similar fashion withrespect to the second and third leg units. Such tripods are known as twostage tripods because they have two fixing means on each leg assembly.

Such tripods have found wide acceptance and are used throughout theworld. Although they are popular, such tripods suffer from thedisadvantage of requiring two fixing means on each leg assembly to beoperated to properly adjust the height thereof. This can be timeconsuming. Moreover, the lower fixing means frequently require that theuser bend over in order to operate them. This can be inconvenient andcause difficulty if the tripod has heavy camera gear mounted thereon.

One possible solution to the above difficulties has been proposed byAustralian Patent No 709257 in the name of Sachtler Agreement(equivalent to U.S. Pat. No. 5,887,835). In this patent, the actuatingmeans for actuating the first fixing means is also connected to thesecond fixing means such that operating the first actuating means tolock the first fixing means also simultaneously locks the second fixingmeans. Similarly, operating the first actuating means to unlock thefirst fixing means also simultaneously unlocks the second fixing means.Thus, locking and unlocking of each leg assembly of the tripod issimplified.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a support means ofadjustable height comprising at least one leg assembly having a firstleg unit, a second leg unit and a third leg unit, said first and secondleg units being slidably movable relative to each other, said second andthird leg units being slidably movable relative to each other, firstfixing means for selectively locking and unlocking the first leg unitrelative to the second leg unit, second fixing means for selectivelylocking and unlocking the third leg unit relative to the second legunit, first actuating means for selectively actuating the first fixingmeans between locked and unlocked positions and second actuating meansfor selectively actuating the second fixing means between locked andunlocked positions, characterised in that the first and second actuatingmeans are independently actuatable to selectively and independently lockor unlock the first fixing means and the second fixing means and thefirst actuating means and the second actuating means are positioned inclose proximity to each other such that the first actuating means andthe second actuating means can be operated essentially simultaneously bya user to thereby essentially simultaneously lock or unlock the firstfixing means and the second fixing means.

It is preferred that the first actuating means and the second actuatingmeans are operable by the hand of the user.

The first actuating means and the second actuating means are preferablypositioned substantially adjacent to each other. Preferably, the secondactuating means is positioned adjacent to and below the first actuatingmeans.

In one embodiment, the second actuating means is positioned away fromthe second fixing means. In this embodiments, the second actuating meansmay be connected to the second fixing means by a connecting member.Operation of the second actuating means will cause the connecting memberto also actuate and move the second fixing means from the lockedposition to the unlocked position and vice versa. The connecting meanssuitably comprises a torsion bar.

The support means of the present invention is preferably a tripod,especially a tripod used for supporting camera equipment. Such tripodsare known and include a platform to which the camera equipment (such ascameras and fluid heads) may be mounted, and three leg assembliesattached to the platform. Such tripods may have a number of fixing meansused to lock the leg assemblies into place when the tripod is correctlyadjusted. The present invention encompasses all such fixing means.

An especially suitable fixing means comprises a clamping means forclamping the leg units to prevent relative movement of the leg units.

In one embodiment of the present invention, the first actuating meanscomprises a first lever and the second actuating means comprises asecond lever. The first and second levers may operate by rotating aroundrespective pivot points. The first and second levers may also include aneccentric such that the levers can be moved to overcome a dead centre tothereby lock the respective fixing means. Again, such arrangements areknown and need not be described further.

The support means of the present invention is preferably arranged suchthat the first fixing means and the second fixing means are mounted at afixed spacing, more preferably with both fixing means mounted to thesecond leg unit. This will ensure that the distance between the firstand second fixing means does not vary. The second leg unit is preferablyan intermediate leg unit, with the first leg unit being an upper legunit and the third leg unit being a lower leg unit.

The second leg unit may comprise a plurality of legs spaced laterallyapart, with a first cross member extending between the legs to hold thelegs in spaced apart relationship. The first cross-members may includereceiving means for slidably receiving one or more legs of the first legunit. The first fixing means may operate by clamping the one or morelegs of the first leg unit. In this fashion, the height of the first legunit relative to the second leg unit can be adjusted.

Alternatively, the leg(s) of the first leg unit may be telescopicallyslidable in the legs of the second leg unit.

The second leg unit may also have a second cross member extendingbetween the plurality of legs of the second leg unit. The second crossmember also assists in holding the legs of the second leg unit in spacedapart relationship. The second cross member may include receiving meansfor slidably receiving one or more legs of the third leg unit. Thesecond fixing means preferably works by clamping the leg(s) of the thirdleg unit.

Alternatively, the leg(s) of the third leg unit may be telescopicallyreceived within the legs of the second leg unit.

In the embodiment of the present invention which includes first andsecond cross members, the first fixing means is preferably mounted onthe first cross member and the second fixing means is preferably mountedon the second cross member.

The present invention provides a support means of adjustable height inwhich the height can be easily adjusted and the leg units locked intoposition relative to each other by a simplified action. The apparatusalso provides the added flexibility of being able to independently lockthe leg units such that locking the first and second leg units relativeto each other does not necessarily lock the second and third leg unitsrelative to each other. In this regard, the apparatus of the presentinvention can be used in a distinct fashion to the apparatus disclosedin Australian patent no. 709257.

The present invention also encompasses the leg assembly described above.

A preferred embodiment of the present invention will now be describedwith reference to the accompanying drawings in which:

FIG. 1 shows a three-dimensional view of a camera tripod in accordancewith the present invention;

FIG. 2 shows a three-dimensional view of the top cross member of thetripod of FIG. 1 with the first and second actuating means in theunlocked position;

FIG. 3 shows a view generally similar to FIG. 2 but with the topactuating means in the locked position.

FIG. 4 is a similar view to FIG. 1, but with the leg units extended;

FIG. 5 is a cross-sectional view of a first fixing means suitable foruse in the present invention;

FIG. 6 is a cross-sectional view of a second fixing means suitable foruse in the present invention; and

FIGS. 7 and 8 are side views of the apparatus of FIG. 1.

In considering the description hereunder and the accompanying drawings,it will be appreciated that the drawings show a presently preferredembodiment of the invention and the drawings should not be considered torestrict the invention to the specific embodiment shown therein.

Turning firstly to FIG. 1, it will be noted that FIG. 1 shows one legassembly of a tripod. The tripod will, of course, include three legassemblies that are essentially identical to the leg assembly shown inFIG. 1. However, for the sake of clarity, the other two leg assemblieshave been omitted from FIG. 1. The tripod 10, part of which is shown inFIG. 1, includes a platform 11. Platform 11 is designed to have cameraequipment, such as fluid heads and cameras mounted thereto. The tripodfurther includes a first leg assembly 12 and second and third legassemblies (not shown), each leg assembly being mounted to the platform11. The leg assembly 12 is a three-leg unit leg assembly that includesfirst leg unit 13, second leg unit 14 and third leg unit 15. The firstleg unit 13 includes legs 13A and 13B. Similarly, second leg unit 14includes legs 14A and 14B. It can be seen from FIG. 1 that legs 14A and14B of second leg unit 14 are laterally spaced from each other. Thisthird leg unit 15 includes one leg 15A as best shown in FIG. 4.

It will also be noted that third leg unit 15 includes a foot 16 mountedat the lowermost part thereof.

The leg assembly 12 further includes an upper cross member 17 and alower cross member 18. Upper cross member 17 includes openings 19, 20(best shown in FIGS. 2 and 3) for slidably receiving legs 13A and 13Btherein. Upper cross member 17 also includes openings 21, 22 forreceiving legs 14A, 14B of the second leg unit 14. It will beappreciated that the top part of legs 14A, 14B are fixedly received inopenings 21 and 22. Openings 21 and 22 act to hold legs 14A, 14B isspaced apart relationship.

The lower ends of legs 14A, 14B are also received in similar openingsformed in lower cross member 18. This acts to hold the lower ends oflegs 14A, 14B in spaced apart relationship.

It will be appreciated from the above described construction that theupper and lower cross members 17, 18 are spaced apart by a fixed amount,this being the length of the legs 14A, 14B.

Although not clearly shown in the accompanying drawings, the lower crossmember 18 also includes an aperture in the lower part therein to allowthe leg 15A of the third leg unit to pass therethrough, such that theleg 15A of the third leg unit 15 can be slidably moved relative to thelegs 14A, 14B of the second leg unit.

The upper cross member 17 also includes a first fixing means mountedtherein for selectively locking and unlocking the first leg unit inposition relative to the second leg unit. Similarly, the lower crossmember 18 includes a second fixing means for selectively locking andunlocking the third leg unit in position relative to the second legunit. As the first fixing means and second fixing means are mountedwithin respective upper and lower cross members 17, 18, they are notvisible and therefore are not shown in FIGS. 1 to 3. It will beappreciated that the fixing means may be of any construction known to besuitable to those skilled in the art.

The leg assembly 12 shown in FIGS. 1 to 3 also includes a firstactuating means 23 which takes the form of a lever pivotally mounted toupper cross member 17. The lever 23 can be moved from an open position,as shown in FIGS. 1 and 2, to a closed position, as shown in FIG. 3. Inthe open position shown in FIGS. 1 and 2, the first fixing means is inthe unlocked position and the first leg unit can slide freely relativeto the second leg unit. In the closed position shown in FIG. 3, thefirst actuating means locks the first fixing means such that the firstleg unit 13 is locked against movement relative to the second leg unit14, thereby locking the first leg unit into position relative to thesecond leg unit.

The apparatus further includes a second actuating means 24 that isconnected via torsion bar 25 to the second fixing means mounted withinlower cross member 18. As can be best seen from FIGS. 1 and 2, secondactuating means 24 is in the form of a lever that is positionedsubstantially adjacent to and below first actuating means or lever 23.The positioning of the second actuating means 24 in close proximity tofirst actuating means 23 allows the hand of a user to engage both firstand second actuating means 23, 24 simultaneously to thereby enableessentially simultaneous actuation of first and second actuating means23, 24 to thereby selectively lock or unlock both the first fixing meansand the second fixing means. It will be appreciated that actuation ofsecond actuating means 24 causes rotation of torsion bar 25 which thenacts on the second fixing means to move the second fixing means betweenthe locked and unlocked positions. Second actuating means 24 is mountedindependently to first actuating means 23 in the embodiment shown in theFigures

It will be appreciated that first actuating means 23 and secondactuating means 24 are not connected to each other. This enables firstactuating means 23 to be actuated separately and independently to secondactuating means 24 (and vice versa). Therefore, it is possible tooperate the first fixing means without operating the second fixing means(and vice versa). For example, as shown in FIG. 3, the first actuatingmeans 23 has been moved to the locked position, thereby locking firstfixing means such that the first leg unit is fixed relative to thesecond leg unit, whilst the second actuating means 24 has not beenoperated such that the second fixing means is still in the unlockedstate, thereby allowing relative movement between the second leg unitand the third leg unit. This enables further adjustment of the third legunit to take place.

It will also be appreciated that the positioning of the second actuatingmeans 24 in the embodiments shown in the drawings is well above theposition of the second fixing means. In normal use of the apparatus ofthe invention, this places the second actuating means 24 at a much moreconvenient height for the user. It will be appreciated that, in mostprior art tripods, the second actuating means was located on the lowercross member 18. This required the user to bend over to operate thesecond actuating means. It will also be appreciated that the presentinvention also encompasses other positioning of the first and secondactuating means. For example, the first and second actuating means maybe located near the second locking means, or both may be positionedintermediate the first and second locking means or above the first andsecond locking means. However, the positioning as shown in FIGS. 1 to 4and 7 and 8 is most preferred.

Specific embodiments of currently preferred constructions for the firstand second fixing means are shown in FIGS. 5 and 6. It will beappreciated that the fixing means shown in FIGS. 5 and 6 are onlyexamples of suitable fixing means that may be used in the presentinvention and that the present invention extends to include use allsuitable fixing means.

The fixing means shown in FIG. 5 is preferably the upper fixing means.It includes a main body portion 30 having arcuate extensions 31, 32 thatact to form part of openings 33, 34 through which legs 13A, 13B canslidably pass when the fixing means is unlocked. A clamping plate 35 isattached to the main body portion 30 by a bolt 36 and nut 37. A springmay be provided on the shank of bolt 36 to bias the clamping plate 35away from the main body portion 30 when the fixing means is in theunlocked position. Alternatively, and as shown in FIG. 5, springs orother biasing means 50, 51 may be provided at locations away from thebolt to bias the clamping plate away from the main-body portion 30.

The head of bolt 36 has lever 23 pivotally attached thereto such thatlever 23 can rotate about pivot point 38. Lever 23 has an eccentric 39formed thereon which allows the lever 23 to be biased into either thelocked position or unlocked position by moving the lever 23 through adead centre.

When the fixing means shown in FIG. 5 is in the locked position, theclamping plate 35 bears against the legs 13A, 13B to thereby lock thoselegs against sliding movement. When it is in the unlocked position, theclamping plate 35 does not contact or only loosely contacts the legs13A, 13B to thereby allow slidable movement of the legs through holes33, 34.

A suitable construction for the lower fixing means is shown in FIG. 6.The lower fixing means includes a main body portion 40 that definesholes 41, 42 for receiving the lower ends of legs 14A, 14B. Holes 41, 42preferably have closed lower ends. Legs 14A and 14B are suitably fixedin holes 41, 42. Hole 44, through which leg 15A of the third leg unitcan slidably move, is defined by intermediate body portion 43 andclamping member 45. Intermediate body portion 43 is part of main bodyportion 40. Main body portion 40 also includes housing 46 for receivingtorsion rod 25.

Bolts 47, 48 pass through main body portion 40 and extend from clampingmember 45 to housing 46. As can be seen from FIG. 6, the end of torsionrod 25 that fits into housing 46 has an eccentric shape. When thetorsion rod 25 is in the position shown in FIG. 6, housing member 46 isurged away from intermediate body portion 43. This in turn pullsclamping member 45 towards the main body portion 40 (and theintermediate body portion 43) by bolts 47, 48 and clamps the outer wallof leg 15A against sliding movement. In this position, the fixing meansshown in FIG. 6 is locked. If the torsion rod 25 is moved in ananti-clockwise direction by actuating lever 24 in that direction, flatland 49 of torsion rod 25 is positioned adjacent intermediate bodyportion 43 such that clamping member 45 can move away from intermediatebody portion 43. In this position, the clamping members 43, 45 do notcontact or only loosely contact leg 15A, thereby allowing slidablemovement of leg 15A through hole 44. It is preferred that clampingmember 45 is biased such that it tends to move away from intermediatebody portion 43 in the unlocked position.

From FIG. 6, it can be seen that rotation of the torsion rod 25 byactuation of lever 24 can lock and unlock the second fixing means.

A side view of the apparatus of the present invention is shown in FIGS.7 and 8. In FIG. 8, levers 23, 24 are in the locked position. FIG. 7 and8 show that torsion rod 25 is positioned laterally from the three legunits 13, 14, 15. However, the torsion rod 25 may be positionedco-planar with the leg units if desired, or even positioned within oneof legs 14A or 14B.

Those skilled in the art will appreciate that the present invention maybe subject to variations and modifications other than those specificallydisclosed. It is to be understood that the present invention encompassesall such variations and modifications that fall within its spirit andscope.

1. A support means of adjustable height comprising at least one legassembly having a first leg unit, a second leg unit and a third legunit, said first and second leg units being slidably movable relative toeach other, said second and third leg units being slidably movablerelative to each other, first fixing means for selectively locking andunlocking the first leg unit relative to the second leg unit, secondfixing means for selectively locking and unlocking the third leg unitrelative to the second leg unit, first actuating means for selectivelyactuating the first fixing means between locked and unlocked positionsand second actuating means for selectively actuating the second fixingmeans between locked and unlocked positions, characterised in that thefirst and second actuating means are independently actuatable toselectively and independently lock or unlock the first fixing means andthe second fixing means, and that the first actuation means and thesecond actuating means are positioned in close proximity to each othersuch that the first actuating means and the second actuating means canbe operated essentially simultaneously by a user to thereby essentiallysimultaneously lock or unlock the first fixing means and the secondfixing means, irrespective of the positions of the first, second andthird leg units relative to each other.
 2. A support means according toclaim 1 wherein the first actuating means and the second actuating meansare positioned substantially adjacent to each other.
 3. A support meansaccording to claim 2 wherein the second actuating means is positionedadjacent to and below the first actuating means.
 4. A support means asclaimed in any one of claims 1 to 3 wherein the second actuating meansis positioned away from the second fixing means and the second actuatingmeans is connected to the second fixing means by a connecting member. 5.A support means as claimed in claim 4 wherein the connecting membercomprises a torsion bar.
 6. A support means as claimed in claim 1wherein at least one of the first or second fixing means comprises aclamping means for selectively clamping the leg units to preventrelative movement of the leg units.
 7. A support means as claimed inclaim 1 wherein the first actuating means comprises a first lever andthe second actuating means comprises a second lever.
 8. A support meansas claimed in claim 7 wherein the first and second levers rotate aroundrespective pivot points.
 9. A support means as claimed in claim 7wherein the first and second levers include an eccentric such that thelevers can be moved to overcome a dead centre to thereby lock respectivefixing means.
 10. A support means as claimed in claim 1 wherein thefirst fixing means and the second fixing means are mounted to the secondleg unit.
 11. A support means as claimed in claim 10 wherein the secondleg unit comprises a plurality of legs spaced laterally apart, with afirst cross member extending between the legs to hold the legs in spacedapart relationship, the first cross-member including receiving means forslidably receiving one or more legs of the first leg unit, a secondcross member extending between the plurality of legs of the second legunit, the second cross member including receiving means for slidablyreceiving one or more legs of the third leg unit.
 12. A support means asclaimed in claim 11 wherein the first fixing means clamps the one ormore legs of the first leg unit and the second fixing means clamps theone or more legs of the third leg unit.
 13. A support means as claimedin claim 1 wherein the leg units are telescopically slidable relative toeach other.
 14. A support means as claimed in claims 11 or 12 whereinthe first fixing means is mounted on the first cross member and thesecond fixing means is mounted on the second cross member.
 15. A supportmeans as claimed in claim 1 comprising a tripod.
 16. A leg assemblyhaving a first leg unit, a second leg unit and a third leg unit, saidfirst and second leg units being slidably movable relative to eachother, said second and third leg units being slidably movable relativeto each other, first fixing means for selectively locking and unlockingthe first leg unit relative to the second leg unit, second fixing meansfor selectively locking and unlocking the third leg unit relative to thesecond leg unit, first actuating means for selectively actuating thefirst fixing means between locked and unlocked positions and secondactuating means for selectively actuating the second fixing meansbetween locked and unlocked positions, characterised in that the firstand second actuating means are independently actuatable to selectivelyand independently lock and unlock the first fixing means and the secondfixing means and the first actuating means respectively, and that thesecond actuating means are positioned in close proximity to each othersuch that the first actuating means and the second actuating means canbe operated essentially simultaneously by a user to thereby essentiallysimultaneously lock or unlock the first fixing means and the secondfixing means, irrespective of the positions of the first, second andthird leg units relative to each other.